Patent Literature Nos. 1 and 2 and Non-Patent Literature Nos. 1 and 2 below disclose optical modulators having a ridge optical waveguide. Each of the optical modulators disclosed in Patent Literature No. 1 and Non-Patent Literature No. 1 below has an overhang-shaped signal electrode provided on the ridge optical waveguide, and each of the optical modulators disclosed in Patent Literature No. 2 and Non-Patent Literature No. 2 below has a signal electrode having a mushroom shape.